294 lines
12 KiB
Python
294 lines
12 KiB
Python
import os
|
|
import json
|
|
import binascii
|
|
import logging
|
|
import typing
|
|
import asyncio
|
|
import re
|
|
from collections import OrderedDict
|
|
from cryptography.hazmat.primitives.ciphers.algorithms import AES
|
|
from lbry.blob import MAX_BLOB_SIZE
|
|
from lbry.blob.blob_info import BlobInfo
|
|
from lbry.blob.blob_file import AbstractBlob, BlobFile
|
|
from lbry.utils import get_lbry_hash_obj
|
|
from lbry.error import InvalidStreamDescriptorError
|
|
|
|
log = logging.getLogger(__name__)
|
|
|
|
RE_ILLEGAL_FILENAME_CHARS = re.compile(
|
|
r'('
|
|
r'[<>:"/\\|?*]+|' # Illegal characters
|
|
r'[\x00-\x1F]+|' # All characters in range 0-31
|
|
r'[ \t]*(\.)+[ \t]*$|' # Dots at the end
|
|
r'(^[ \t]+|[ \t]+$)|' # Leading and trailing whitespace
|
|
r'^CON$|^PRN$|^AUX$|' # Illegal names
|
|
r'^NUL$|^COM[1-9]$|^LPT[1-9]$' # ...
|
|
r')'
|
|
)
|
|
|
|
|
|
def format_sd_info(stream_name: str, key: str, suggested_file_name: str, stream_hash: str,
|
|
blobs: typing.List[typing.Dict]) -> typing.Dict:
|
|
return {
|
|
"stream_type": "lbryfile",
|
|
"stream_name": stream_name,
|
|
"key": key,
|
|
"suggested_file_name": suggested_file_name,
|
|
"stream_hash": stream_hash,
|
|
"blobs": blobs
|
|
}
|
|
|
|
|
|
def random_iv_generator() -> typing.Generator[bytes, None, None]:
|
|
while 1:
|
|
yield os.urandom(AES.block_size // 8)
|
|
|
|
|
|
def read_bytes(file_path: str, offset: int, to_read: int):
|
|
with open(file_path, 'rb') as f:
|
|
f.seek(offset)
|
|
return f.read(to_read)
|
|
|
|
|
|
async def file_reader(file_path: str):
|
|
length = int(os.stat(file_path).st_size)
|
|
offset = 0
|
|
|
|
while offset < length:
|
|
bytes_to_read = min((length - offset), MAX_BLOB_SIZE - 1)
|
|
if not bytes_to_read:
|
|
break
|
|
blob_bytes = await asyncio.get_event_loop().run_in_executor(
|
|
None, read_bytes, file_path, offset, bytes_to_read
|
|
)
|
|
yield blob_bytes
|
|
offset += bytes_to_read
|
|
|
|
|
|
def sanitize_file_name(dirty_name: str, default_file_name: str = 'lbry_download'):
|
|
file_name, ext = os.path.splitext(dirty_name)
|
|
file_name = re.sub(RE_ILLEGAL_FILENAME_CHARS, '', file_name)
|
|
ext = re.sub(RE_ILLEGAL_FILENAME_CHARS, '', ext)
|
|
|
|
if not file_name:
|
|
log.warning('Unable to sanitize file name for %s, returning default value %s', dirty_name, default_file_name)
|
|
file_name = default_file_name
|
|
if len(ext) > 1:
|
|
file_name += ext
|
|
|
|
return file_name
|
|
|
|
|
|
class StreamDescriptor:
|
|
__slots__ = [
|
|
'loop',
|
|
'blob_dir',
|
|
'stream_name',
|
|
'key',
|
|
'suggested_file_name',
|
|
'blobs',
|
|
'stream_hash',
|
|
'sd_hash'
|
|
]
|
|
|
|
def __init__(self, loop: asyncio.AbstractEventLoop, blob_dir: str, stream_name: str, key: str,
|
|
suggested_file_name: str, blobs: typing.List[BlobInfo], stream_hash: typing.Optional[str] = None,
|
|
sd_hash: typing.Optional[str] = None):
|
|
self.loop = loop
|
|
self.blob_dir = blob_dir
|
|
self.stream_name = stream_name
|
|
self.key = key
|
|
self.suggested_file_name = suggested_file_name
|
|
self.blobs = blobs
|
|
self.stream_hash = stream_hash or self.get_stream_hash()
|
|
self.sd_hash = sd_hash
|
|
|
|
@property
|
|
def length(self) -> int:
|
|
return len(self.as_json())
|
|
|
|
def get_stream_hash(self) -> str:
|
|
return self.calculate_stream_hash(
|
|
binascii.hexlify(self.stream_name.encode()), self.key.encode(),
|
|
binascii.hexlify(self.suggested_file_name.encode()),
|
|
[blob_info.as_dict() for blob_info in self.blobs]
|
|
)
|
|
|
|
def calculate_sd_hash(self) -> str:
|
|
h = get_lbry_hash_obj()
|
|
h.update(self.as_json())
|
|
return h.hexdigest()
|
|
|
|
def as_json(self) -> bytes:
|
|
return json.dumps(
|
|
format_sd_info(binascii.hexlify(self.stream_name.encode()).decode(), self.key,
|
|
binascii.hexlify(self.suggested_file_name.encode()).decode(),
|
|
self.stream_hash,
|
|
[blob_info.as_dict() for blob_info in self.blobs]), sort_keys=True
|
|
).encode()
|
|
|
|
def old_sort_json(self) -> bytes:
|
|
blobs = []
|
|
for blob in self.blobs:
|
|
blobs.append(OrderedDict(
|
|
[('length', blob.length), ('blob_num', blob.blob_num), ('iv', blob.iv)] if not blob.blob_hash else
|
|
[('length', blob.length), ('blob_num', blob.blob_num), ('blob_hash', blob.blob_hash), ('iv', blob.iv)]
|
|
))
|
|
if not blob.blob_hash:
|
|
break
|
|
return json.dumps(
|
|
OrderedDict([
|
|
('stream_name', binascii.hexlify(self.stream_name.encode()).decode()),
|
|
('blobs', blobs),
|
|
('stream_type', 'lbryfile'),
|
|
('key', self.key),
|
|
('suggested_file_name', binascii.hexlify(self.suggested_file_name.encode()).decode()),
|
|
('stream_hash', self.stream_hash),
|
|
])
|
|
).encode()
|
|
|
|
def calculate_old_sort_sd_hash(self) -> str:
|
|
h = get_lbry_hash_obj()
|
|
h.update(self.old_sort_json())
|
|
return h.hexdigest()
|
|
|
|
async def make_sd_blob(self, blob_file_obj: typing.Optional[AbstractBlob] = None,
|
|
old_sort: typing.Optional[bool] = False,
|
|
blob_completed_callback: typing.Optional[typing.Callable[['AbstractBlob'], None]] = None):
|
|
sd_hash = self.calculate_sd_hash() if not old_sort else self.calculate_old_sort_sd_hash()
|
|
if not old_sort:
|
|
sd_data = self.as_json()
|
|
else:
|
|
sd_data = self.old_sort_json()
|
|
sd_blob = blob_file_obj or BlobFile(self.loop, sd_hash, len(sd_data), blob_completed_callback, self.blob_dir)
|
|
if blob_file_obj:
|
|
blob_file_obj.set_length(len(sd_data))
|
|
if not sd_blob.get_is_verified():
|
|
writer = sd_blob.get_blob_writer()
|
|
writer.write(sd_data)
|
|
|
|
await sd_blob.verified.wait()
|
|
sd_blob.close()
|
|
return sd_blob
|
|
|
|
@classmethod
|
|
def _from_stream_descriptor_blob(cls, loop: asyncio.AbstractEventLoop, blob_dir: str,
|
|
blob: AbstractBlob) -> 'StreamDescriptor':
|
|
with blob.reader_context() as blob_reader:
|
|
json_bytes = blob_reader.read()
|
|
try:
|
|
decoded = json.loads(json_bytes.decode())
|
|
except json.JSONDecodeError:
|
|
blob.delete()
|
|
raise InvalidStreamDescriptorError("Does not decode as valid JSON")
|
|
if decoded['blobs'][-1]['length'] != 0:
|
|
raise InvalidStreamDescriptorError("Does not end with a zero-length blob.")
|
|
if any(blob_info['length'] == 0 for blob_info in decoded['blobs'][:-1]):
|
|
raise InvalidStreamDescriptorError("Contains zero-length data blob")
|
|
if 'blob_hash' in decoded['blobs'][-1]:
|
|
raise InvalidStreamDescriptorError("Stream terminator blob should not have a hash")
|
|
if any(i != blob_info['blob_num'] for i, blob_info in enumerate(decoded['blobs'])):
|
|
raise InvalidStreamDescriptorError("Stream contains out of order or skipped blobs")
|
|
descriptor = cls(
|
|
loop, blob_dir,
|
|
binascii.unhexlify(decoded['stream_name']).decode(),
|
|
decoded['key'],
|
|
binascii.unhexlify(decoded['suggested_file_name']).decode(),
|
|
[BlobInfo(info['blob_num'], info['length'], info['iv'], info.get('blob_hash'))
|
|
for info in decoded['blobs']],
|
|
decoded['stream_hash'],
|
|
blob.blob_hash
|
|
)
|
|
if descriptor.get_stream_hash() != decoded['stream_hash']:
|
|
raise InvalidStreamDescriptorError("Stream hash does not match stream metadata")
|
|
return descriptor
|
|
|
|
@classmethod
|
|
async def from_stream_descriptor_blob(cls, loop: asyncio.AbstractEventLoop, blob_dir: str,
|
|
blob: AbstractBlob) -> 'StreamDescriptor':
|
|
if not blob.is_readable():
|
|
raise InvalidStreamDescriptorError(f"unreadable/missing blob: {blob.blob_hash}")
|
|
return await loop.run_in_executor(None, cls._from_stream_descriptor_blob, loop, blob_dir, blob)
|
|
|
|
@staticmethod
|
|
def get_blob_hashsum(blob_dict: typing.Dict):
|
|
length = blob_dict['length']
|
|
if length != 0:
|
|
blob_hash = blob_dict['blob_hash']
|
|
else:
|
|
blob_hash = None
|
|
blob_num = blob_dict['blob_num']
|
|
iv = blob_dict['iv']
|
|
blob_hashsum = get_lbry_hash_obj()
|
|
if length != 0:
|
|
blob_hashsum.update(blob_hash.encode())
|
|
blob_hashsum.update(str(blob_num).encode())
|
|
blob_hashsum.update(iv.encode())
|
|
blob_hashsum.update(str(length).encode())
|
|
return blob_hashsum.digest()
|
|
|
|
@staticmethod
|
|
def calculate_stream_hash(hex_stream_name: bytes, key: bytes, hex_suggested_file_name: bytes,
|
|
blob_infos: typing.List[typing.Dict]) -> str:
|
|
h = get_lbry_hash_obj()
|
|
h.update(hex_stream_name)
|
|
h.update(key)
|
|
h.update(hex_suggested_file_name)
|
|
blobs_hashsum = get_lbry_hash_obj()
|
|
for blob in blob_infos:
|
|
blobs_hashsum.update(StreamDescriptor.get_blob_hashsum(blob))
|
|
h.update(blobs_hashsum.digest())
|
|
return h.hexdigest()
|
|
|
|
@classmethod
|
|
async def create_stream(
|
|
cls, loop: asyncio.AbstractEventLoop, blob_dir: str, file_path: str, key: typing.Optional[bytes] = None,
|
|
iv_generator: typing.Optional[typing.Generator[bytes, None, None]] = None,
|
|
old_sort: bool = False,
|
|
blob_completed_callback: typing.Optional[typing.Callable[['AbstractBlob'],
|
|
asyncio.Task]] = None) -> 'StreamDescriptor':
|
|
blobs: typing.List[BlobInfo] = []
|
|
|
|
iv_generator = iv_generator or random_iv_generator()
|
|
key = key or os.urandom(AES.block_size // 8)
|
|
blob_num = -1
|
|
async for blob_bytes in file_reader(file_path):
|
|
blob_num += 1
|
|
blob_info = await BlobFile.create_from_unencrypted(
|
|
loop, blob_dir, key, next(iv_generator), blob_bytes, blob_num, blob_completed_callback
|
|
)
|
|
blobs.append(blob_info)
|
|
blobs.append(
|
|
BlobInfo(len(blobs), 0, binascii.hexlify(next(iv_generator)).decode())) # add the stream terminator
|
|
file_name = os.path.basename(file_path)
|
|
suggested_file_name = sanitize_file_name(file_name)
|
|
descriptor = cls(
|
|
loop, blob_dir, file_name, binascii.hexlify(key).decode(), suggested_file_name, blobs
|
|
)
|
|
sd_blob = await descriptor.make_sd_blob(old_sort=old_sort, blob_completed_callback=blob_completed_callback)
|
|
descriptor.sd_hash = sd_blob.blob_hash
|
|
return descriptor
|
|
|
|
def lower_bound_decrypted_length(self) -> int:
|
|
length = sum(blob.length - 1 for blob in self.blobs[:-2])
|
|
return length + self.blobs[-2].length - (AES.block_size // 8)
|
|
|
|
def upper_bound_decrypted_length(self) -> int:
|
|
return self.lower_bound_decrypted_length() + (AES.block_size // 8)
|
|
|
|
@classmethod
|
|
async def recover(cls, blob_dir: str, sd_blob: 'AbstractBlob', stream_hash: str, stream_name: str,
|
|
suggested_file_name: str, key: str,
|
|
blobs: typing.List['BlobInfo']) -> typing.Optional['StreamDescriptor']:
|
|
descriptor = cls(asyncio.get_event_loop(), blob_dir, stream_name, key, suggested_file_name,
|
|
blobs, stream_hash, sd_blob.blob_hash)
|
|
|
|
if descriptor.calculate_sd_hash() == sd_blob.blob_hash: # first check for a normal valid sd
|
|
old_sort = False
|
|
elif descriptor.calculate_old_sort_sd_hash() == sd_blob.blob_hash: # check if old field sorting works
|
|
old_sort = True
|
|
else:
|
|
return
|
|
await descriptor.make_sd_blob(sd_blob, old_sort)
|
|
return descriptor
|